<?php

class Message
{
    protected $value = '';
    protected $time = 0;

    public function __construct($value)
    {
        $this->value = "{$value}";
        $this->time = microtime(true);
    }

    public function value()
    {
        return $this->value;
    }

    public function time()
    {
        return $this->time;
    }
}

class ResponseMessage extends Message
{
}

class RequestMessage extends Message
{
}

?>